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<FONT color="green">001</FONT>    // Copyright (c) 2011, Mike Samuel<a name="line.1"></a>
<FONT color="green">002</FONT>    // All rights reserved.<a name="line.2"></a>
<FONT color="green">003</FONT>    //<a name="line.3"></a>
<FONT color="green">004</FONT>    // Redistribution and use in source and binary forms, with or without<a name="line.4"></a>
<FONT color="green">005</FONT>    // modification, are permitted provided that the following conditions<a name="line.5"></a>
<FONT color="green">006</FONT>    // are met:<a name="line.6"></a>
<FONT color="green">007</FONT>    //<a name="line.7"></a>
<FONT color="green">008</FONT>    // Redistributions of source code must retain the above copyright<a name="line.8"></a>
<FONT color="green">009</FONT>    // notice, this list of conditions and the following disclaimer.<a name="line.9"></a>
<FONT color="green">010</FONT>    // Redistributions in binary form must reproduce the above copyright<a name="line.10"></a>
<FONT color="green">011</FONT>    // notice, this list of conditions and the following disclaimer in the<a name="line.11"></a>
<FONT color="green">012</FONT>    // documentation and/or other materials provided with the distribution.<a name="line.12"></a>
<FONT color="green">013</FONT>    // Neither the name of the OWASP nor the names of its contributors may<a name="line.13"></a>
<FONT color="green">014</FONT>    // be used to endorse or promote products derived from this software<a name="line.14"></a>
<FONT color="green">015</FONT>    // without specific prior written permission.<a name="line.15"></a>
<FONT color="green">016</FONT>    // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS<a name="line.16"></a>
<FONT color="green">017</FONT>    // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT<a name="line.17"></a>
<FONT color="green">018</FONT>    // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS<a name="line.18"></a>
<FONT color="green">019</FONT>    // FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE<a name="line.19"></a>
<FONT color="green">020</FONT>    // COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,<a name="line.20"></a>
<FONT color="green">021</FONT>    // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,<a name="line.21"></a>
<FONT color="green">022</FONT>    // BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;<a name="line.22"></a>
<FONT color="green">023</FONT>    // LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER<a name="line.23"></a>
<FONT color="green">024</FONT>    // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT<a name="line.24"></a>
<FONT color="green">025</FONT>    // LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN<a name="line.25"></a>
<FONT color="green">026</FONT>    // ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE<a name="line.26"></a>
<FONT color="green">027</FONT>    // POSSIBILITY OF SUCH DAMAGE.<a name="line.27"></a>
<FONT color="green">028</FONT>    <a name="line.28"></a>
<FONT color="green">029</FONT>    package org.owasp.html;<a name="line.29"></a>
<FONT color="green">030</FONT>    <a name="line.30"></a>
<FONT color="green">031</FONT>    import javax.annotation.Nullable;<a name="line.31"></a>
<FONT color="green">032</FONT>    <a name="line.32"></a>
<FONT color="green">033</FONT>    import com.google.common.collect.ImmutableSet;<a name="line.33"></a>
<FONT color="green">034</FONT>    <a name="line.34"></a>
<FONT color="green">035</FONT>    /**<a name="line.35"></a>
<FONT color="green">036</FONT>     * An attribute policy for attributes whose values are URLs that requires that<a name="line.36"></a>
<FONT color="green">037</FONT>     * the value have no protocol or have an allowed protocol.<a name="line.37"></a>
<FONT color="green">038</FONT>     *<a name="line.38"></a>
<FONT color="green">039</FONT>     * &lt;p&gt;<a name="line.39"></a>
<FONT color="green">040</FONT>     * URLs with protocols must match the protocol set passed to the constructor.<a name="line.40"></a>
<FONT color="green">041</FONT>     * URLs without protocols but which specify an origin different from the<a name="line.41"></a>
<FONT color="green">042</FONT>     * containing page (e.g. {@code //example.org}) are only allowed if the<a name="line.42"></a>
<FONT color="green">043</FONT>     * {@link FilterUrlByProtocolAttributePolicy#allowProtocolRelativeUrls policy}<a name="line.43"></a>
<FONT color="green">044</FONT>     * allows both {@code http} and {@code https} which are normally used to serve<a name="line.44"></a>
<FONT color="green">045</FONT>     * HTML.<a name="line.45"></a>
<FONT color="green">046</FONT>     * Same-origin URLs, URLs without any protocol or authority part are always<a name="line.46"></a>
<FONT color="green">047</FONT>     * allowed.<a name="line.47"></a>
<FONT color="green">048</FONT>     * &lt;/p&gt;<a name="line.48"></a>
<FONT color="green">049</FONT>     *<a name="line.49"></a>
<FONT color="green">050</FONT>     * &lt;p&gt;<a name="line.50"></a>
<FONT color="green">051</FONT>     * This class assumes that URLs are either hierarchical, or are opaque, but<a name="line.51"></a>
<FONT color="green">052</FONT>     * do not look like they contain an authority portion.<a name="line.52"></a>
<FONT color="green">053</FONT>     * &lt;/p&gt;<a name="line.53"></a>
<FONT color="green">054</FONT>     *<a name="line.54"></a>
<FONT color="green">055</FONT>     * @author Mike Samuel &lt;mikesamuel@gmail.com&gt;<a name="line.55"></a>
<FONT color="green">056</FONT>     */<a name="line.56"></a>
<FONT color="green">057</FONT>    @TCB<a name="line.57"></a>
<FONT color="green">058</FONT>    public class FilterUrlByProtocolAttributePolicy implements AttributePolicy {<a name="line.58"></a>
<FONT color="green">059</FONT>      private final ImmutableSet&lt;String&gt; protocols;<a name="line.59"></a>
<FONT color="green">060</FONT>    <a name="line.60"></a>
<FONT color="green">061</FONT>      public FilterUrlByProtocolAttributePolicy(<a name="line.61"></a>
<FONT color="green">062</FONT>          Iterable&lt;? extends String&gt; protocols) {<a name="line.62"></a>
<FONT color="green">063</FONT>        this.protocols = ImmutableSet.copyOf(protocols);<a name="line.63"></a>
<FONT color="green">064</FONT>      }<a name="line.64"></a>
<FONT color="green">065</FONT>    <a name="line.65"></a>
<FONT color="green">066</FONT>      public @Nullable String apply(<a name="line.66"></a>
<FONT color="green">067</FONT>          String elementName, String attributeName, String s) {<a name="line.67"></a>
<FONT color="green">068</FONT>        protocol_loop:<a name="line.68"></a>
<FONT color="green">069</FONT>        for (int i = 0, n = s.length(); i &lt; n; ++i) {<a name="line.69"></a>
<FONT color="green">070</FONT>          switch (s.charAt(i)) {<a name="line.70"></a>
<FONT color="green">071</FONT>            case '/': case '#': case '?':  // No protocol.<a name="line.71"></a>
<FONT color="green">072</FONT>              // Check for domain relative URLs like //www.evil.org/<a name="line.72"></a>
<FONT color="green">073</FONT>              if (s.startsWith("//")<a name="line.73"></a>
<FONT color="green">074</FONT>                  // or the protocols by which HTML is normally served are OK.<a name="line.74"></a>
<FONT color="green">075</FONT>                  &amp;&amp; !allowProtocolRelativeUrls()) {<a name="line.75"></a>
<FONT color="green">076</FONT>                return null;<a name="line.76"></a>
<FONT color="green">077</FONT>              }<a name="line.77"></a>
<FONT color="green">078</FONT>              break protocol_loop;<a name="line.78"></a>
<FONT color="green">079</FONT>            case ':':<a name="line.79"></a>
<FONT color="green">080</FONT>              String protocol = Strings.toLowerCase(s.substring(0, i));<a name="line.80"></a>
<FONT color="green">081</FONT>              if (!protocols.contains(protocol)) { return null; }<a name="line.81"></a>
<FONT color="green">082</FONT>              break protocol_loop;<a name="line.82"></a>
<FONT color="green">083</FONT>          }<a name="line.83"></a>
<FONT color="green">084</FONT>        }<a name="line.84"></a>
<FONT color="green">085</FONT>        return normalizeUri(s);<a name="line.85"></a>
<FONT color="green">086</FONT>      }<a name="line.86"></a>
<FONT color="green">087</FONT>    <a name="line.87"></a>
<FONT color="green">088</FONT>      protected boolean allowProtocolRelativeUrls() {<a name="line.88"></a>
<FONT color="green">089</FONT>        return protocols.contains("http") &amp;&amp; protocols.contains("https");<a name="line.89"></a>
<FONT color="green">090</FONT>      }<a name="line.90"></a>
<FONT color="green">091</FONT>    <a name="line.91"></a>
<FONT color="green">092</FONT>      /** Percent encodes anything that looks like a colon, or a parenthesis. */<a name="line.92"></a>
<FONT color="green">093</FONT>      static String normalizeUri(String s) {<a name="line.93"></a>
<FONT color="green">094</FONT>        int n = s.length();<a name="line.94"></a>
<FONT color="green">095</FONT>        boolean colonsIrrelevant = false;<a name="line.95"></a>
<FONT color="green">096</FONT>        for (int i = 0; i &lt; n; ++i) {<a name="line.96"></a>
<FONT color="green">097</FONT>          char ch = s.charAt(i);<a name="line.97"></a>
<FONT color="green">098</FONT>          switch (ch) {<a name="line.98"></a>
<FONT color="green">099</FONT>            case '/': case '#': case '?': case ':':<a name="line.99"></a>
<FONT color="green">100</FONT>              colonsIrrelevant = true;<a name="line.100"></a>
<FONT color="green">101</FONT>              break;<a name="line.101"></a>
<FONT color="green">102</FONT>            case '(': case ')': case '\uff1a':<a name="line.102"></a>
<FONT color="green">103</FONT>              StringBuilder sb = new StringBuilder(n + 16);<a name="line.103"></a>
<FONT color="green">104</FONT>              int pos = 0;<a name="line.104"></a>
<FONT color="green">105</FONT>              for (; i &lt; n; ++i) {<a name="line.105"></a>
<FONT color="green">106</FONT>                ch = s.charAt(i);<a name="line.106"></a>
<FONT color="green">107</FONT>                switch (ch) {<a name="line.107"></a>
<FONT color="green">108</FONT>                  case '(':<a name="line.108"></a>
<FONT color="green">109</FONT>                    sb.append(s, pos, i).append("%28");<a name="line.109"></a>
<FONT color="green">110</FONT>                    pos = i + 1;<a name="line.110"></a>
<FONT color="green">111</FONT>                    break;<a name="line.111"></a>
<FONT color="green">112</FONT>                  case ')':<a name="line.112"></a>
<FONT color="green">113</FONT>                    sb.append(s, pos, i).append("%29");<a name="line.113"></a>
<FONT color="green">114</FONT>                    pos = i + 1;<a name="line.114"></a>
<FONT color="green">115</FONT>                    break;<a name="line.115"></a>
<FONT color="green">116</FONT>                  default:<a name="line.116"></a>
<FONT color="green">117</FONT>                    if (ch &gt; 0x100 &amp;&amp; !colonsIrrelevant) {<a name="line.117"></a>
<FONT color="green">118</FONT>                      // Other colon like characters.<a name="line.118"></a>
<FONT color="green">119</FONT>                      // TODO: do we need to encode non-colon characters if we're<a name="line.119"></a>
<FONT color="green">120</FONT>                      // not dealing with URLs that haven't been copy/pasted into<a name="line.120"></a>
<FONT color="green">121</FONT>                      // the URL bar?<a name="line.121"></a>
<FONT color="green">122</FONT>                      // Is it safe to assume UTF-8 here?<a name="line.122"></a>
<FONT color="green">123</FONT>                      switch (ch) {<a name="line.123"></a>
<FONT color="green">124</FONT>                        case '\u0589':<a name="line.124"></a>
<FONT color="green">125</FONT>                          sb.append(s, pos, i).append("%d6%89");<a name="line.125"></a>
<FONT color="green">126</FONT>                          pos = i + 1;<a name="line.126"></a>
<FONT color="green">127</FONT>                          break;<a name="line.127"></a>
<FONT color="green">128</FONT>                        case '\u05c3':<a name="line.128"></a>
<FONT color="green">129</FONT>                          sb.append(s, pos, i).append("%d7%83");<a name="line.129"></a>
<FONT color="green">130</FONT>                          pos = i + 1;<a name="line.130"></a>
<FONT color="green">131</FONT>                          break;<a name="line.131"></a>
<FONT color="green">132</FONT>                        case '\u2236':<a name="line.132"></a>
<FONT color="green">133</FONT>                          sb.append(s, pos, i).append("%e2%88%b6");<a name="line.133"></a>
<FONT color="green">134</FONT>                          pos = i + 1;<a name="line.134"></a>
<FONT color="green">135</FONT>                          break;<a name="line.135"></a>
<FONT color="green">136</FONT>                        case '\uff1a':<a name="line.136"></a>
<FONT color="green">137</FONT>                          sb.append(s, pos, i).append("%ef%bc%9a");<a name="line.137"></a>
<FONT color="green">138</FONT>                          pos = i + 1;<a name="line.138"></a>
<FONT color="green">139</FONT>                          break;<a name="line.139"></a>
<FONT color="green">140</FONT>                      }<a name="line.140"></a>
<FONT color="green">141</FONT>                    }<a name="line.141"></a>
<FONT color="green">142</FONT>                    break;<a name="line.142"></a>
<FONT color="green">143</FONT>                }<a name="line.143"></a>
<FONT color="green">144</FONT>              }<a name="line.144"></a>
<FONT color="green">145</FONT>              return sb.append(s, pos, n).toString();<a name="line.145"></a>
<FONT color="green">146</FONT>          }<a name="line.146"></a>
<FONT color="green">147</FONT>        }<a name="line.147"></a>
<FONT color="green">148</FONT>        return s;<a name="line.148"></a>
<FONT color="green">149</FONT>      }<a name="line.149"></a>
<FONT color="green">150</FONT>    <a name="line.150"></a>
<FONT color="green">151</FONT>      @Override<a name="line.151"></a>
<FONT color="green">152</FONT>      public boolean equals(Object o) {<a name="line.152"></a>
<FONT color="green">153</FONT>        return o != null &amp;&amp; this.getClass() == o.getClass()<a name="line.153"></a>
<FONT color="green">154</FONT>            &amp;&amp; protocols.equals(((FilterUrlByProtocolAttributePolicy) o).protocols);<a name="line.154"></a>
<FONT color="green">155</FONT>      }<a name="line.155"></a>
<FONT color="green">156</FONT>    <a name="line.156"></a>
<FONT color="green">157</FONT>      @Override<a name="line.157"></a>
<FONT color="green">158</FONT>      public int hashCode() {<a name="line.158"></a>
<FONT color="green">159</FONT>        return protocols.hashCode();<a name="line.159"></a>
<FONT color="green">160</FONT>      }<a name="line.160"></a>
<FONT color="green">161</FONT>    <a name="line.161"></a>
<FONT color="green">162</FONT>    }<a name="line.162"></a>




























































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